Clip Advancer

ABSTRACT

A surgical clip applier and methods for applying surgical clips to a vessel, duct, shunt, etc., during a surgical procedure are provided. In one embodiment, a surgical clip applier is provided and can include a shaft having a proximal end and a distal end with opposed jaws thereon, a guide member disposed within the shaft and configured to guide a clip into the opposed jaws, the guide member having a channel formed in a surface thereof, and an advancer movably disposed within the shaft and configured to advance a clip over the guide member and into the opposed jaws, the advancer having a distal tip that slidably engages the channel for maintaining contact with a surgical clip as it is advanced into the opposed jaws. In other embodiments, the guide member can also include a proximal channel formed in a superior surface thereof. The advancer can be configured to deflect downward into the proximal channel to move proximally beneath an inferior surface of the apex of the clip to position itself proximally to the clip to advance the clip into the opposed jaws.

FIELD OF THE INVENTION

The present invention relates broadly to surgical devices, and in particular to methods and devices for applying surgical clips to ducts, vessels, shunts, etc.

BACKGROUND OF THE INVENTION

Surgical clip appliers are commonly used for ligating blood vessels, ducts, shunts, or a portion of body tissue during surgery. Most clip appliers typically have a handle with an elongate shaft having a pair of movable opposed jaws formed on an end thereof for holding and forming a ligation clip therebetween. The jaws are positioned around the vessel or duct, and the clip is crushed or formed on the vessel by the closing of the jaws.

Clip appliers that are configured to deliver multiple clips typically include an advancer mechanism that sequentially advances the clips into the jaws of the clip applier. Many clip appliers have jaws that are angled with respect to the shaft for better visibility. The angled jaws require that a clip being fed into the jaws change orientation. This change in orientation can lead to misalignment between the advancer mechanism and the clip, which can result in the clip being improperly fed into the jaws, further resulting in a malformed clip being delivered to the tissue. Problems can also arise as the advancer mechanism retracts behind the next clip and fails to engage the clip to advance it into the jaws.

Accordingly, there remains a need for improved methods and devices for applying surgical clips to vessels, ducts, shunts, etc.

SUMMARY OF THE INVENTION

The present invention provides method and devices for applying a surgical clip to a vessel, duct, shunt, etc. In one embodiment, a surgical clip applier is provided and can include a shaft having a proximal end and a distal end with opposed jaws thereon. A guide member can be disposed within the shaft and it can be configured to guide a clip into the opposed jaws. The guide member can include a channel formed in a surface thereof. The device can also include an advancer movably disposed within the shaft and configured to advance a clip over the guide member and into the opposed jaws. The advancer can have a distal tip that slidably engages the channel for maintaining contact with a surgical clip as it is advanced into the opposed jaws.

In one embodiment, the distal tip can have a distal-facing surface that is configured to abut an apex of a surgical clip to advance the surgical clip into the opposed jaws. The distal-facing surface of the distal tip can have a height that is greater than a depth of the channel. In one embodiment, the channel of the guide member can be in the form of an opening formed through the guide member. A proximal portion of the channel can have a ramped surface formed thereon and configured to abut against a proximal portion of the distal tip to cause a distal portion of the distal tip to deflect away from the guide member during proximal movement of the advancer. A distal portion of the channel can also have a ramped surface formed thereon and configured to abut against a distal portion of the distal tip to cause the distal portion of the distal tip to deflect away from the guide member during distal movement of the advancer. The guide member can also include a longitudinally-extending groove formed therein and configured to substantially prevent lateral movement of the distal tip relative to opposed lateral sidewalls of the guide member.

The device can also include at least one clip disposed within the shaft. In one embodiment, the clip can have a maximum height measured in a direction transverse to a longitudinal axis of the shaft, and the distal tip can have a maximum height measured in a direction transverse to a longitudinal axis of the shaft that is greater than the height of the at least one clip. In other aspects, the guide member can be in the form of or can include a tissue stop having a distal end with a recess formed therein for receiving tissue. The opposed jaws can be configured to engage opposed legs of a surgical clip such that an apex of the surgical clip is maintained a distance above the guide member during advancement of the surgical clip into the opposed jaws.

In another embodiment, a surgical clip applier is provided and includes a shaft having opposed jaws on a distal end thereof The opposed jaws can be movable between open and closed positions for applying a clip to tissue. A clip advancer can be movably disposed within the shaft and it can have a distal tip configured to advance at least one clip into the opposed jaws. The device can also include an advancer guide disposed within the elongate shaft. The advancer guide can have a ramped surface formed thereon and configured to cause a distal portion of the distal tip to deflect away from the guide member during proximal movement of the advancer to position the distal tip behind an apex of a surgical clip disposed within the shaft. In one embodiment, the ramped surface can be a proximal ramped surface, and the guide member can include a distal ramped surface configured to cause the distal portion of the distal tip to deflect in a direction away from the guide member during distal movement of the advancer. The advancer guide can include a channel formed therein, and the proximal ramped surface can be formed adjacent to a proximal end of the channel, and the distal ramped surface can be formed adjacent to a distal end of the channel. In another embodiment, the distal tip can have a distal-facing surface that has a height that is greater than a depth of the channel in the advancer guide. The advancer guide can also include a distal longitudinally-extending groove formed therein and configured to slidably receive the distal tip of the advancer guide.

A method for advancing a clip into opposed jaws of a clip applier is also provided, and in one embodiment the method includes actuating a trigger to cause an advancer to move distally through a shaft and to contact and advance a surgical clip distally along a superior surface of a guide member and into opposed jaws of the clip applier. The advancer can have a distal tip with a distal-facing surface that allows an apex of the surgical clip to move in superior and inferior directions while still maintaining contact with the apex of the surgical clip. The method can also include releasing the trigger to move the advancer proximally. The distal tip of the advancer can deflect in an inferior direction beneath an inferior surface of a second surgical clip during proximal movement of the advancer. In an exemplary embodiment, as the advancer moves proximally, the guide member can cause the distal tip of the advancer to deflect in a superior direction to position the distal tip of the advancer at a location proximal to a second surgical clip. In other embodiments, the guide member can include a channel formed therein that maintains the distal tip of the advancer in alignment with a longitudinal axis of the guide member. The advancer tip can maintain contact with an apex of the clip as the clip is formed between the opposed jaws.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1A is a side view of one exemplary embodiment of a surgical clip applier;

FIG. 1B is an exploded view of the surgical clip applier shown in FIG. 1A;

FIG. 2A is a top view of a jaw retainer assembly of the surgical clip applier shown in FIG. 1A;

FIG. 2B is a bottom view of the jaw retainer assembly shown in FIG. 2A;

FIG. 2C is a side view of the jaw retainer assembly shown in FIG. 2B;

FIG. 2D is a cross-sectional view of the jaw retainer assembly shown in FIG. 2C taken across line D-D;

FIG. 3A is a top view of a feeder shoe for use with the jaw retainer assembly shown in FIGS. 2A-2D;

FIG. 3B is a bottom view of the feeder shoe shown in FIG. 3A;

FIG. 4A is a side perspective view of a feed bar that is configured to advance the feeder shoe of FIGS. 3A and 3B through the jaw retainer assembly shown in FIGS. 2A-2D;

FIG. 4B is a side view of the proximal end of the feed bar shown in FIG. 4A and the proximal end of the jaw retainer shaft shown in FIGS. 2A and 2B, showing the feed bar in a proximal-most position;

FIG. 4C is a side view of the feed bar and jaw retainer shaft shown in FIG. 4B, showing the feed bar in a distal-most position;

FIG. 4D is a side view of another embodiment of a proximal end of a feed bar shown in connection with the proximal end of the jaw retainer shaft shown in FIGS. 2A and 2B, showing the feed bar in the proximal-most position;

FIG. 4E is a side view of the feed bar and jaw retainer shaft shown in FIG. 4D, showing the feed bar in a distal-most position;

FIG. 4F is a side view of yet another embodiment of a proximal end of a feed bar shown in connection with the proximal end of the jaw retainer shaft shown in FIGS. 2A and 2B, showing the feed bar in the proximal-most position;

FIG. 4G is a side view of the feed bar and jaw retainer shaft shown in FIG. 4F, showing the feed bar in an intermediate position;

FIG. 4H is a side view of the feed bar and jaw retainer shaft shown in FIG. 4F, showing the feed bar in a distal-most position;

FIG. 5A is a side perspective view of an advancer that is configured to couple to a distal end of the feed bar shown in FIG. 4A;

FIG. 5B is a side perspective view of another embodiment of an advancer that is configured to couple to a distal end of the feed bar shown in FIG. 4A;

FIG. 5C is a perspective view of still another embodiment of an advancer that is configured to couple to a distal end of the feed bar shown in FIG. 4A;

FIG. 5D is another perspective view of the advancer of FIG. 5C;

FIG. 6A is a cross-sectional view of a clip advancing assembly, which includes the jaw retainer assembly shown in FIGS. 2A-2D, the feeder shoe shown in FIGS. 3A-3B, and the feed bar shown in FIG. 4A, showing the feed bar in an initial, proximal position relative to the clip track of the jaw retainer assembly;

FIG. 6B is a cross-sectional view of the clip advancing assembly shown in FIG. 6A, showing the feed bar moved in a distal direction;

FIG. 6C is a cross-sectional view of the clip advancing assembly shown in FIG. 6B, showing the feed bar moved further distally, thereby moving the feeder shoe and a clip supply disposed distally of the feeder shoe in a distal direction;

FIG. 6D is a cross-sectional view of the clip advancing assembly shown in FIG. 6C, showing the feed bar returned to the initial, proximal position, shown in FIG. 6A, while the feeder shoe and clip supply remain in the advanced position shown in FIG. 6C;

FIG. 6E is a bottom perspective view of the advancer shown in FIG. 5A disposed within the clip track of the jaw retainer assembly shown in FIGS. 2A-2D, showing the advancer in a proximal-most position;

FIG. 6F is a bottom perspective view of the advancer shown in FIG. 6E, showing the advancer in a distal-most position after advancing a clip into the jaws of the surgical clip applier;

FIG. 7 is a side perspective view of a pair of jaws of the surgical clip applier shown in FIG. 1A;

FIG. 8 is a side perspective view of a cam for use with the jaws shown in FIG. 7;

FIG. 9 is a top perspective view of a push rod that is adapted to couple to the cam shown in FIG. 8 for moving the cam relative to the jaws shown in FIG. 7;

FIG. 10A is a top view of the cam shown in FIG. 8 coupled to the jaws shown in FIG. 7, showing the cam in an initial position and the jaws open;

FIG. 10B is a top view of the cam shown in FIG. 8 coupled to the jaws shown in FIG. 7, showing the cam advanced over the jaws and the jaws in a closed position;

FIG. 11A is a top perspective view of a tissue stop that is adapted to couple to a distal end of the clip track of the jaw retainer assembly shown in FIGS. 2A-2D;

FIG. 11B is a top perspective view of another embodiment of a tissue stop having a ramp formed thereon for guiding a clip into the jaws and stabilizing the clip during clip formation;

FIG. 11C is a side view of the tissue stop shown in FIG. 11B;

FIG. 11D is an enlarged view of the tissue stop shown in FIGS. 11B and 11C;

FIG. 11E is a perspective view of another embodiment of a tissue stop that is adapted to couple to a distal end of the clip track of the jaw retainer assembly shown in FIGS. 2A-2D;

FIG. 11F is another perspective view of the tissue stop of FIG. 11E;

FIG. 12A is a top view of a distal end of the surgical clip applier shown in FIG. 1A showing the tissue stop of FIG. 11A positioned between the jaws of FIG. 7;

FIG. 12B is perspective view of the advancer of FIG. 5C advancing a clip over the tissue stop of FIG. 11E;

FIG. 12C is a perspective view of the advancer of FIG. 5C in a distal position on the tissue stop of FIG. 11E;

FIG. 12D is a perspective view of the advancer of FIG. 5C deflecting under a distal-most clip within a channel formed in the tissue stop of FIG. 11E;

FIG. 12E is a perspective view of the advancer of FIG. 5C in a proximal position on the tissue stop of FIG. 11E;

FIG. 13 is a side, partially cross-sectional view of the handle portion of the surgical clip applier shown in FIG. 1A;

FIG. 14 is a side perspective view of a trigger insert of the surgical clip applier shown in FIG. 1A;

FIG. 15A is a side perspective view of one half of a feed bar coupler of the surgical clip applier shown in FIG. 1A;

FIG. 15B is a side perspective view of the other half of the feed bar coupler shown in FIG. 15A;

FIG. 16 is a top perspective view of a flexible link that forms part of a clip advancing assembly of the surgical clip applier shown in FIG. 1A;

FIG. 17A is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 1A, showing a clip advancing assembly in an initial position;

FIG. 17B is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 17A, showing the clip advancing assembly partially actuated;

FIG. 17C is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 17B, showing the clip advancing assembly fully actuated;

FIG. 17D is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 17A, showing a clip forming assembly actuated;

FIG. 18 is a side view of a closure link roller that forms part of a clip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 19 is a top perspective view of a closure link that couples to the closure link roller shown in FIG. 18 to form part of a clip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 20A is a top perspective view of a closure link coupler that couples to the closure link shown in FIG. 19 and that also forms part of the clip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 20B is a bottom view of the closure link coupler shown in FIG. 20A coupled to the push rod of FIG. 9 and having one embodiment of a biasing element disposed therein;

FIG. 20C is a bottom view of the closure link shown in FIG. 20A coupled to the push rod of FIG. 9 and having another embodiment of a biasing element disposed therein;

FIG. 20D is a chart showing the amount of force required to displace the biasing element shown in FIG. 20B;

FIG. 20E is a side view of another embodiment of a portion of a closure link coupler having ridges formed therein;

FIG. 21A is an enlarged side perspective view of an anti-backup mechanism of the surgical clip applier shown in FIG. 1A;

FIG. 21B is a perspective view of a pawl mechanism of the anti-backup mechanism shown in FIG. 21A;

FIG. 22A is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 1A, showing the anti-backup mechanism in an initial position;

FIG. 22B is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 22A, showing the anti-backup mechanism in a partially actuated position;

FIG. 22C is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 22B, showing the anti-backup mechanism in a fully actuated position;

FIG. 22D is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 22C, showing the anti-backup mechanism returning to an initial position; and

FIG. 22E is a side, partially cross-sectional view of a portion of the handle of the surgical clip applier shown in FIG. 22D, showing the anti-backup mechanism returned to the initial position.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally provides a surgical clip applier and methods for using a surgical clip applier to apply surgical clips to a vessel, duct, shunt, etc., during a surgical procedure. An exemplary surgical clip applier can include a variety of features to facilitate application of a surgical clip, as described herein and illustrated in the drawings. However, a person skilled in the art will appreciate that the surgical clip applier can include only some of these features and/or it can include a variety of other features known in the art. The surgical clip applier described herein is merely intended to represent certain exemplary embodiments.

FIG. 1A illustrates one exemplary surgical clip applier 10. As shown, the clip applier 10 generally includes a housing 12 having a stationary handle 14 and a movable handle or trigger 16 that is pivotally coupled to the housing 12. An elongate shaft 18 extends from the housing 12 and it includes a pair of opposed jaws 20 formed on a distal end thereof for crimping a surgical clip. The elongate shaft 18 can be rotatably coupled to the housing 12, and it can include a rotation knob 22 for rotating the shaft 18 relative to the housing 12. FIG. 1B illustrates an exploded view of the surgical clip applier 10 shown in FIG. 1A, and the various components will be described in more detail below.

FIGS. 2A-12 illustrate exemplary embodiments of the various components of the shaft 18 of the surgical clip applier 10. In general, referring to FIG. 1B, the shaft 18 includes an outer tube 24 that houses the shaft components, which can include a jaw retaining assembly 26 having a jaw retainer shaft 28 with a clip track 30 and a push rod channel 32 formed thereon. The jaws 20 can be configured to mate to a distal end of the clip track 30. The shaft assembly 18 can also include a clip advancing assembly, which in one exemplary embodiment can include a feeder shoe 34 that is adapted to be slidably disposed within the clip track 30 to advance a series of clips 36 positioned therein, and a feed bar 38 that is adapted to drive the feeder shoe 34 through the clip track 30. The feed bar 38 can include an advancer assembly 40 that is adapted to mate to a distal end thereof for advancing a distal-most clip into the jaws 20. The shaft assembly 18 can also include a clip forming or camming assembly, which in one exemplary embodiment can include a cam 42 that is adapted to slidably mate to the jaws 20, and a push rod 44 that can couple to the cam 42 to move the cam 42 relative to the jaws 20. The shaft assembly can also include a tissue stop 46 that can mate to a distal end of the clip track 30 for facilitating positioning of the jaws 20 relative to a surgical site.

The various components of one exemplary clip advancing assembly are shown in more detail in FIGS. 2A-5. Referring first to FIGS. 2A-2D, the jaw retaining assembly 26 is shown and it includes an elongate, substantially planar jaw retainer shaft 28 having a proximal end 28 a that mates to the outer tube 24, and a distal end 28 b that is adapted to mate to the jaws 20. While a variety of techniques can be used to mate the proximal end 28 a of the jaw retainer shaft 28 to the outer tube 24, in the illustrated embodiment the proximal end 28 a includes teeth 31 formed on opposed sides thereof that are adapted to be received within corresponding holes or openings (not shown) formed in the outer tube 24, and a cut-out 29 formed therein that allows the opposed sides of the proximal end 28 a to deflect or to form a spring. In particular, the cut-out 29 allows the opposed sides of the proximal end 28 a of the jaw retainer shaft 28 to be compressed toward one another when the jaw retainer shaft 28 is inserted in the outer tube 24. Once the teeth 31 are aligned with the corresponding openings in the outer tube 24, the proximal end 28 a of the jaw retainer shaft 28 will return to its original, uncompressed configuration thereby causing the teeth 31 to extend into the corresponding openings to engage the outer 24. As will be discussed in more detail below with respect to FIG. 4A, the device can also include a feature to prevent compression of the opposed sides of the proximal end 28 a of the jaw retainer shaft 28 during use of the device to prevent accidental disengagement of the teeth 31 from the outer tube 24.

A variety of techniques can also be used to mate the distal end 28 b of the jaw retainer shaft 28 to the jaws 20, however in the illustrated embodiment the distal end 28 b of the jaw retainer shaft 28 includes several cut-outs or teeth 78 formed therein for mating with corresponding protrusions or teeth 94 formed on the jaws 20, which will be discussed in more detail below with respect to FIG. 7. The teeth 78 allow a proximal portion of the jaws 20 to be substantially co-planar with the jaw retainer shaft 28.

The jaw retaining assembly 26 can also include a push rod channel 32 formed thereon for slidably receiving the push rod 44, which is used to advanced the cam 42 over the jaws 20, as will be discussed in more detail below. The push rod channel 32 can be formed using a variety of techniques, and it can have any shape and size depending on the shape and size of the push rod 44. As shown in FIG. 2D, the push rod channel 32 is fixedly attached, e.g., by welding, to a superior surface of the retainer shaft 28, and it has a substantially rectangular shape and defines a pathway 32 a extending therethrough. The push rod channel 32 can also extend along all or only a portion of the retainer shaft 28. A person skilled in the art will appreciate that the jaw retaining assembly 26 does not need to include a push rod channel 32 for facilitating movement of the push rod 44 within the elongate shaft 18 of the surgical clip applier 10.

As is further shown in FIGS. 2A-2D, the jaw retaining assembly 26 can also include a clip track 30 mated thereto or formed thereon. The clip track 30 is shown mated to an inferior surface of the jaw retainer shaft 28, and it extends distally beyond the distal end 28 b of the jaw retainer shaft 28 to allow a distal end 30 b of the clip track 30 to be substantially aligned with the jaws 20. In use, the clip track 30 is configured to seat at least one, and preferably a series, of clips therein. Accordingly, the clip track 30 can include opposed side rails 80 a, 80 b that are adapted to seat opposed legs of one or more clips therein, such that the legs of the clips are axially aligned with one another. In an exemplary embodiment, the clip track 30 can be configured to seat about twenty clips that are pre-disposed within the clip track 30 during manufacturing. A person skilled in the art will appreciate that the shape, size, and configuration of the clip track 30 can vary depending on the shape, size, and configuration of clips, or other closure devices such as staples, adapted to be received therein. Moreover, a variety of other techniques can be used, instead of a clip track 30, to retain a clip supply with the elongate shaft 18.

The clip track 30 can also include several openings 30 c formed therein for receiving a tang 82 a formed on a feeder shoe 34 adapted to be disposed within the clip track 30, as will be discussed in more detail below. In an exemplary embodiment, the clip track 30 includes a quantity of openings 30 c that corresponds to at least the number of clips adapted to be pre-disposed within the device 10 and applied during use. The openings 30 c are preferably equidistant from one another to ensure that the tang 82 a on the feeder shoe 34 engages an opening 30 c each time the feeder shoe 34 is advanced. While not shown, the clip track 30 can include detents, rather than openings 30 c, or it can include other features that allow the clip track 30 to engage the feeder shoe 34 and prevent distal movement, yet allow proximal movement, of the feeder shoe 34. The clip track 30 can also include a stop tang 118 formed thereon, as shown in FIG. 2B, that is effective to be engaged by a corresponding stop tang formed on the feeder shoe 34 to prevent movement of the feeder shoe 34 beyond a distal-most position, as will be discussed below. The stop tang 118 can have a variety of configurations, but in one exemplary embodiment it is in the form of two adjacent tabs that extend toward one another to enclose a portion of the clip track, thus allowing clips to pass therethrough.

An exemplary feeder shoe 34 is shown in more detail in FIGS. 3A and 3B, and it can be adapted to directly driving clips through the clip track 30. While the feeder shoe 34 can have a variety of configurations, and a variety of other techniques can be used to drive clips through the clip track 30, in an exemplary embodiment the feeder shoe 34 has a generally elongate shape with proximal and distal ends 34 a, 34 b. The distal end 34 b can be adapted to cradle the proximal-most clip in the clip track 30 to push the clip(s) through the clip track 30. In the illustrated exemplary embodiment, the distal end 34 b is substantially v-shaped for seating a v-shaped bight portion of a clip. The distal end 34 b also includes a rectangular-shaped notch 34 c formed therein for allowing the advancer 40 to engage a distal-most clip and advance it into the jaws 20, as will be discussed in more detail below. The distal end 34 b can, of course, vary depending on the configuration of the clip, or other closure mechanism, being used with the device 10.

In another exemplary embodiment, the feeder shoe 34 can also include features to facilitate distal movement of the feeder shoe 34 within the clip track 30, and to substantially prevent proximal movement of the feeder shoe 34 within the clip track 30. Such a configuration will ensure advancement and proper positioning of the clips within the clip track 30, thus allowing a distal-most clip to be advanced between the jaws 20 with each actuation of the trigger 16, as will be discussed in more detail below. In the illustrated exemplary embodiment, the feeder shoe 34 includes a tang 82 a formed on a superior surface 34 s thereof and angled proximally for engaging one of the openings 30 c formed in the clip track 30. In use, the angle of the tang 82 a allows the feeder shoe 34 to slide distally within the clip track 30. Each time the feeder shoe 34 is advanced, the tang 82 a will move in a distal direction from one opening 30 c to the next opening 30 c in the clip track 30. The engagement of the tang 82 a with the opening 30 c in the clip track 30 will prevent the feeder shoe 34 from moving proximally to return to the previous position, as will be described in more detail below.

In order to facilitate proximal movement of the feeder shoe 34 within the clip track 30, the feeder shoe 34 can also include a tang 82 b formed on the inferior surface 34 i thereof, as shown in FIG. 3B, for allowing the feeder shoe 34 to be engaged by the feed bar 38 (FIG. 4A) as the feed bar 38 is moved distally. The inferior tang 82 b is similar to the superior tang 82 a in that it can be angled proximally. In use, each time the feed bar 38 is moved distally, a detent 84 formed in the feed bar 38 can engage the inferior tang 82 b and move the feeder shoe 34 distally a predetermined distance within the clip track 30. The feed bar 38 can then be moved proximally to return to its initial position, and the angle of the inferior tang 82 b will allow the tang 82 b to slide into the next detent 84 formed in the feed bar 38. As previously noted, a variety of other features rather than tangs 82 a, 82 b and openings 30 c or detents 84 can be used to control movement of the feeder shoe 34 within the clip track 30.

As previously mentioned, the feeder shoe 34 can also include a stop formed thereon that is adapted to stop movement of the feeder shoe 34 when the feeder shoe 34 is in the distal-most position and there are no clips remaining in the device 10. While the stop can have a variety of configurations, FIGS. 3A and 3B illustrate a third tang 82 c formed on the feeder shoe 34 and extending in an inferior direction for engaging the stop tang 118 (FIG. 2B) formed on the clip track 30. The third tang 82 c is positioned such that it will engage the stop tang 118 on the clip track 30 when the feeder shoe 34 is in a distal-most position, thereby preventing movement of the feeder shoe 34 and the feed bar 38 when the clip supply is depleted.

FIG. 4A illustrates an exemplary feed bar 38 for driving the feeder shoe 34 through the clip track 30 of the jaw retaining assembly 26. As shown, the feed bar 38 has a generally elongate shape with proximal and distal ends 38 a, 38 b. The proximal end 38 a of the feed bar 38 a can be adapted to mate to a feed bar coupler 50 (FIG. 1B), which will be discussed in more detail below. The feed bar coupler 50 can mate to a feed link 52 that is effective, upon actuation of the trigger 16, to slidably move the feed bar 38 in a distal direction within the elongate shaft 18. The distal end 38 b of the feed bar 38 b can be adapted to mate to an advancer 40, 40′, exemplary embodiments of which are shown in FIGS. 5A and 5B, that is effective to drive a distal-most clip disposed within the clip track 30 into the jaws 20, which will be discussed in more detail below.

As previously mentioned, the proximal end 38 a of the feed bar 38 can include a feature to prevent compression of the opposed sides of the proximal end 28 a of the jaw retainer shaft 28 (FIGS. 2A and 2B) during use of the device to prevent accidental disengagement of the teeth 31 from the outer tube 24. In one exemplary embodiment, shown FIGS. 4A-4C, the proximal end 38 a of the feed bar 38 can include a protrusion 39 formed thereon that is adapted to extend into the opening 29 formed in the proximal end 28 a of the jaw retainer shaft 28. When the feed bar 38 is in a proximal-most position (i.e., when the trigger 16 is in an open position), the protrusion 39 will be positioned at the proximal end of the opening 29, as shown in FIG. 4B, allowing the proximal end 28 a of the jaw retainer shaft 28 to compress to allow the shaft 28 to slide into the outer tube 24. When the feed bar 38 is in a distal-most position (i.e., when the trigger 16 is in at least a partially closed position), the protrusion 39 will be positioned at an intermediate location adjacent to the teeth 31 as shown in FIG. 4C, to prevent compression of the proximal end 28 a of the jaw retainer shaft 28. This is particularly advantageous during use of the device, as the protrusion 39 will prevent accidental disengagement of the jaw retainer shaft 28 from the outer tube 24 during use of the device. While FIGS. 4A-4C illustrate a protrusion 39 having a rectangular cross-sectional shape with rounded edges, the protrusion 39 can have a variety of other shapes and sizes. For example, as shown in FIGS. 4D and 4E, the protrusion 39′ has a cross-sectional shape that is somewhat triangular with a tapering end that is adapted to extend between the teeth 31 to further ensure that the proximal end 28 a of the jaw retainer shaft 28 can not be compressed during use of the device. More than one protrusion can also be used. For example, FIGS. 4F-4H illustrate another embodiment in which the proximal end 38 a′ of the feed bar 38 includes two protrusions 39 a, 39 b formed thereon and spaced a distance apart from one another. The two protrusions 39 a, 39 b will prevent compression of the proximal end 28 a of the jaw retainer shaft 28 when the feed bar 38 is in a proximal-most position, as shown in FIG. 4F, and when the feed bar 38 is in a distal-most position, as shown in FIG. 4H. Compression of the proximal end 28 a of the jaw retainer shaft 28 can only occur when the feed bar 38 is at an intermediate position such that the teeth 31 are positioned between the protrusions 39 a, 39 b, as shown in FIG. 4G.

As was also previously mentioned, the feed bar 38 can include one or more detents 84 formed therein for engaging the inferior tang 82 b formed on the feeder shoe 34. The quantity of detents 84 can vary, but in an exemplary embodiment the feed bar 38 has a quantity of detents 84 that corresponds to or is greater than a quantity of clips adapted to be delivered by the device 10, and more preferably it has one more detent 84 than the quantity of clips adapted to be delivered by the device 10. By way of non-limiting example, the feed bar 38 can include eighteen detents 84 formed therein for delivering seventeen clips that are pre-disposed within the clip track 30. Such a configuration allows the feed bar 38 to advance the feeder shoe 34 seventeen times, thereby advancing seventeen clips into the jaws 20 for application. The detents 84 are also preferably equidistant from one another to ensure that the feeder shoe 34 is engaged and advanced by the feed bar 38 each time the feed bar 38 is advanced.

The feed bar 38 can also include a feature to control the amount of movement of the feed bar 38 relative to the clip track 30. Such a configuration will ensure that the feeder shoe 34 is advanced a predetermined distance each time the trigger 16 is actuated, thereby advancing only a single clip into the jaws 20. While a variety of techniques can be used to control the distal of movement of the feed bar 38, in an exemplary embodiment the feed bar 38 can include a protrusion 86 formed thereon that is adapted to be slidably received within a corresponding slot 88 (FIG. 2B) formed in the jaw retainer shaft 28. The length of the slot 88 is effective to limit movement of the protrusion 86 therein, thus limiting movement of the feed bar 38. Accordingly, in use the feed bar 38 can slide between a fixed proximal position and a fixed distal position with respect to the clip track 30, thereby allowing the feed bar 38 to advance the feeder shoe 34 by a predetermined distance with each advancement of the feed bar 38.

FIG. 5A illustrates one exemplary embodiment of an advancer 40 that is adapted to mate to the distal end 38 b of the feed bar 38 and which is effective to drive a distal-most clip from the clip track 30 into the jaws 20. A variety of techniques can be used to mate the advancer 40 to the feed bar 38, but in the illustrated embodiment the proximal end 40a of the advancer 40 is in the form of a female connector that is adapted to receive the male connector formed on the distal end 38 b of the feed bar 38. The advancer 40 preferably fixedly mates to the feed bar 38, however it can optionally be integrally formed with the feed bar 38. The distal end 40 b of the feed bar 38 is preferably adapted to advance a clip into the jaws 20 and thus the distal end 40 b of the advancer 40 can include, for example, a clip-pusher member 90 formed thereon. The clip-pusher member 90 can have a variety of shapes and sizes, but in one exemplary embodiment it has an elongate shape with a recess 92 formed in the distal end thereof for seating the bight portion of a clip. The shape of the recess 92 can vary depending on the particular configuration of the clip. The clip-pusher member 90 can also extend at an angle in a superior direction with respect to a longitudinal axis A of the advancer 40. Such a configuration allows the clip-pusher member 90 to extend into the clip track 30 to engage a clip, while the remainder of the advancer 40 extends substantially parallel to the clip track 30.

FIG. 5B illustrates another exemplary embodiment of a clip-pusher member 90′ of an advancer 40′. In this embodiment, the clip-pusher member 90′ is slightly more narrow and it has a small recess 92′ formed in the distal-most end thereof. In use, the advancer 40 can engage and advance only the distal-most clip disposed within the clip track 30 into the jaws 20. This is due to the positioning of the feed bar 38, which is slidably movable between a fixed proximal and distal positions, as previously discussed.

FIGS. 5C and 5D illustrate still another exemplary embodiment of a clip-pusher member or distal tip 90″ of an advancer 40″. In this embodiment, the clip-pusher member or distal tip 90″ has been modified to allow an apex of a surgical clip being advanced into the jaws to move in superior and inferior directions while still maintaining contact with the apex of the surgical clip. In general, the distal tip 90″ has an elongate configuration with a proximal end 90 p″ that is coupled to a body portion or shaft 42″ of the advancer 40″. The shaft 42″ can have various shapes and sizes, but in the illustrated embodiment the shaft 42″ has a generally planar configuration with superior and inferior surfaces 42 s″, 42 i″. The particular configuration of the shaft 42″, with the exception of the distal tip 90″, can be similar to the embodiments previously described herein. In an exemplary embodiment, the distal tip 90″ and the shaft 42″ can be formed as a single integral component, however each component can be formed from different materials. For example, the distal tip 90″ can be formed from a metal, while the entire shaft 42″ or a portion of the shaft 42″ can be formed from a plastic that is integral to the feed bar 38 and is overmolded onto the metal distal tip 90″. Regardless of the particular material used, the distal tip 90″ is preferably formed from a flexible material that allows the tip 90″ to deflect in superior and inferior directions relative to the shaft 42″. In certain exemplary embodiments, the distal tip 90″ can be formed by punching a predetermined shape out of a planar sheet of metal, and then folding opposed sides of the shape together to form the tip as shown, with the inferior surface being hollow.

As indicated above, the distal tip 90″ can be configured to allow an apex of a surgical clip being advanced into the jaws by the tip to move in superior and inferior directions while still maintaining contact with the apex of the clip. In other words, the distal tip 90″ can have a height that is greater than a height of the apex, as measured in the superior/inferior direction (i.e., transverse to the longitudinal axis of the advancer 40″). This will allow the apex of the clip to slide up and down along the tip. In particular, as shown in FIG. 5D, a distal-facing surface 41 of the clip-pusher member 90″ can have a height H, measured in a superior/inferior direction, that is greater than a height (as measured in the same direction) of an apex of a clip pushed by the clip-pusher member 90″, as will be described in more detail below. The increased height can result from a distal biasing surface 43 formed on an inferior surface of the tip 90″ and located adjacent to the distal end 90 d″ of the tip 90″. The distal biasing surface 43 can be in the form of a ramped portion or a surface feature. As further shown in FIGS. 5C and 5D, the distal tip 90″ can also include a proximal biasing surface 45 formed on an inferior surface of the tip 90″ and located adjacent to the proximal end 90 p″ of the tip 90″. The two biasing surfaces 43, 45 can be configured to interact with the tissue stop, as will be described in detail below, and to thereby deflect in superior and inferior directions relative to the tissue stop. The flexible or resilient material used to form the advancer tip 90″ can facilitate repeated bending of the distal tip 90″. As further shown in FIGS. 5C and 5D, a superior or top portion 47 of the clip-pusher member 90″ can be substantially straight and can extend upward at an angle between the proximal end 90 p″ of the tip 90″ and the distal end 90 d″ of the tip 90″. A person skilled in the art will appreciate that the particular configuration of the distal tip 90″ can vary depending on the desired movement of the tip during use.

FIGS. 6A-6G illustrate the clip advancing assembly in use, and in particular FIGS. 6A-6D illustrate movement of the feed bar 38 within the clip track 30 to advance the feeder shoe 34 and clip supply 36, and FIGS. 6E-6F illustrate movement of the advancer 40 to advance a distal-most clip into the jaws 20. The components in the housing 12 that are used to actuate the clip advancing assembly will be discussed in more detail below.

As shown in FIG. 6A, in the resting position the feed bar 38 is in a proximal-most position such that the protrusion 86 is positioned proximally within the elongate slot 88 in the jaw retainer shaft 28. The feeder shoe 34 is disposed within the clip track 30 and, assuming the device 10 has not yet been used, the feeder shoe 34 is in a proximal-most position such that the superior tang 82 a on the feeder shoe 34 is engaged with the proximal-most or first opening 30 c ₁ formed in the clip track 30 to prevent proximal movement of the feeder shoe 34, and the inferior tang 82 b on the feeder shoe 34 is positioned between the first detent 84 ₁ and the second detent 84 ₂ in the feed bar 38, such that the inferior tang 82 b is biased in a superior direction by the feed bar 38. The detents 84 in the feed bar are labeled sequentially as 84 ₁, 84 ₂, etc., and the openings 30 c in the clip track 30 are labeled sequentially as 30 c ₁, 30 c ₂, etc. As is further shown in FIG. 6A, a series of clips 36, labeled sequentially as 36 ₁, 36 ₂, . . . 36 _(x) with 36 _(x) being the distal-most clip, are positioned within the clip track 30 distal of the feeder shoe 34.

Upon actuation of the trigger 16, the feed bar 38 is advanced distally, causing the protrusion 86 to slide distally within the slot 88. As the feed bar 38 moves distally, the inferior tang 82 b on the feeder shoe 34 will slide into the first detent 84 ₁ in the feed bar 38. Further distal movement of the feed bar 38 will cause the first detent 84 ₁ to engage the inferior tang 82 b, as shown in FIG. 6B, and to move the feeder shoe 34 and clip supply 36 ₁, 36 ₂, etc. in a distal direction. As shown in FIG. 6C, when the protrusion 86 abuts the distal end of the elongate slot 88 in the jaw retainer shaft 28, the feed bar 38 is prevented from further distal movement. In this position, the feeder shoe 34 has advanced a predetermined distance to advance the clip supply 36 ₁, 36 ₂, . . . 36 _(x) within the clip track 30 by a predetermined distance. The superior tang 82 a of the feeder shoe 34 has been advanced into the second opening 30 c ₂ in the clip track 30 to prevent proximal movement of the feeder shoe 34, and the inferior tang 82 b on the feeder shoe 34 is still engaged by the first detent 84 ₁ in the feed bar 38.

Movement of the feed bar 38 from the initial, proximal-most position, shown in FIG. 6A, to the final, distal-most position, shown in FIG. 6C, will also advance the distal-most clip 36 _(x) into the jaws 20. In particular, as shown in FIG. 6E, distal movement of the feed bar 38 will cause the clip-pusher member 90 of the advancer 40, which is attached to the distal end of the feed bar 38, to engage the distal-most clip 36 _(x) disposed within the clip track 30 and to advance the clip 36 _(x) into the jaws 20, as shown in FIG. 6F. In an exemplary embodiment, the advancer 40 will engage and initiate advancement of the distal-most clip 36 _(x) prior to engaging and initiating advancement of the feeder shoe 34. As a result the distal-most clip 36 _(x) will advance a distance that is greater than a distance traveled by the feeder shoe 34. Such a configuration allows only the distal-most clip 36 _(x) to be advanced into the jaws 20 without accidentally advancing an additional clip into the jaws 20.

Once the clip 36 _(x) has been partially or fully formed, the trigger 16 can be released to release the formed clip 36 _(x). Release of the trigger 16 will also retract the feed bar 38 in a proximal direction until the protrusion 86 returns to the initial proximal-most position within the elongate slot 88, as shown in FIG. 6D. As the feed bar 38 is retracted proximally, the feeder shoe 34 will not move proximally since the superior tang 82 a will engage the second opening 30 c ₂ in the clip track 30. The inferior tang 82 b will not interfere with proximal movement of the feed bar 38, and once the feed bar 38 is in the initial, proximal-most position, as shown, the inferior tang 82 b will be positioned between the second detent 84 ₂ and the third detent 84 ₃ in the feed bar 38.

The process can be repeated to advance another clip into the jaws 20. With each actuation of the trigger 16, the inferior tang 82 b will be engaged by the next detent, i.e., detent 84 ₂ formed in the feed bar 38, the superior tang 82 a on the feeder shoe 34 will be moved distally into the next opening, i.e., opening 30 c ₃ on the clip track 30, and the distal-most clip will be advanced into the jaws 20 and released. Where the device 10 includes a predetermined amount of clips, e.g., seventeen clips, the trigger 16 can be actuated seventeen times. Once the last clip has been applied, the stop, e.g., the third tang 82 c, on the feeder shoe 34 can engage the stop tang 118 on the clip track 30 to prevent further distal movement of the feeder shoe 34.

The feeder shoe 34, feed bar 38, and/or the clip track 30 can also optionally include features to prevent accidental or unintentional movement of the feeder shoe 34, for example during shipment of the device. This is particularly advantageous as migration of the feeder shoe 34, particularly prior to first use of the device, can cause the device to malfunction. For example, if the feeder shoe 34 migrates distally, the feeder shoe 34 will advance two clips into the jaws simultaneously, thereby resulting in delivery of two misformed clips. Accordingly, in an exemplary embodiment the feeder shoe 34, feed bar 38, and/or the clip track 30 can include an engagement mechanism and/or can be configured to generate a frictional force therebetween that is sufficient to resist movement, but that can be overcome by actuation of the trigger 16 to allow the feed bar to advance the feeder shoe 34 through the clip track 30.

Various techniques can be used to prevent undesirable migration of the feeder shoe 34 within the clip track 30. One exemplary embodiment of a feeder shoe can have a pre-formed cantilevered or bowed configuration in a free state (i.e., when the feeder shoe is removed from the clip track 30) such that the feeder shoe forms a cantilevered spring when disposed within the clip track 30. In particular, a portion of the feeder shoe can include a bend formed therein such that the opposed ends of the feeder shoe are angled relative to one another. The bend can cause the height of the feeder shoe to be greater than the height of the clip track 30. While the height can vary, in an exemplary embodiment the bend is configured to increase a height of the feeder shoe by an amount that is sufficient to create a frictional drag force between the feeder shoe and the clip track 30, but that still allows the feeder shoe to slide within the clip track 30 when the trigger 16 is actuated. In an exemplary embodiment, the height of the feeder shoe is increased at least about 30%, or more preferably about 40%. In use, the clip track 30 will force the feeder shoe into a substantially planar configuration such that the feeder shoe is biased against the clip track 30 when disposed therein. The bend of the feeder shoe, as well as the terminal ends of the feeder shoe, will therefore apply a force to the clip track 30, thereby creating a frictional drag force between the feeder shoe and the clip track 30. The frictional force will prevent the feeder shoe from migrating relative to the clip track 30 unless the trigger 16 is actuated, in which case the force applied by the trigger 16 will overcome the frictional forces.

A person skilled in the art will appreciate that the bend can have a variety of configurations, and it can be formed anywhere along the length of the feeder shoe. The bend can be formed at or near the mid-portion of the feeder shoe. The bend can also extend in various directions. The bend can extend in a direction perpendicular to the axis such that the bend and the ends apply a force to the clip track 30. The bend can alternatively extend along a longitudinal axis of the feeder shoe such that the feeder shoe applies a force to the opposed side rails of the clip track 30. The bend can also angle the opposed ends in a downward direction such that the feeder shoe is substantially A-shaped, or alternatively the bend can angle the opposed ends in an upward direction such that the feeder shoe is substantially V-shaped. The feeder shoe can also include any number of bends formed therein. A person skilled in the art will appreciate that the particular configuration of the bend(s) can be modified based on the properties of the feeder shoe and the clip track 30 to obtain a desired amount of frictional force therebetween.

Another embodiment of a technique for creating frictional forces between the feeder shoe and clip track is provided. In this embodiment, the clip track and/or the feeder shoe can include one or more surface protrusions formed thereon. Two surface protrusions can be formed on the clip track. While the surface protrusions can be formed at various locations on the clip track, including inside the opposed side rails or along the entire length of the clip track, or at various locations on the feeder shoe the two protrusions can be formed adjacent to the proximal end of the clip track and they are positioned to prevent initial migration of the feeder shoe prior to use, e.g., during shipping. The size of the protrusions can vary depending upon the amount of frictional force necessary to prevent unintentional migration of the feeder shoe.

While the protrusions can be configured to provide a sufficient amount of friction to prevent unintentional migration of the feeder shoe, the feeder shoe and/or clip track can optionally include a feature that is adapted to engage corresponding surface protrusions. Opposed tangs formed on a distal portion of the feeder shoe for engaging the protrusions on the clip track. The tangs can vary in shape and size, and they can include a lip or other protrusion configured to engage or “catch” the protrusions. The tangs extend toward one another from opposed sidewalls of the feeder show.

Another embodiment of a technique for preventing unintentional migration of the feeder shoe is provided. In this embodiment, friction is generated between the feeder shoe and the feed bar. In particular, the feeder shoe can include a tang with a lip formed thereon, and the feed bar can include a corresponding groove formed therein. In use, the lip is configured to engage the groove to prevent unintentional migration of the feeder shoe. The lip and groove, however, are configured to allow movement of the feeder shoe when a sufficient force is applied to the feeder shoe by actuation of the trigger 16.

A person skilled in the art will appreciate that a variety of other techniques can be used to prevent unintentional migration of a feeder shoe or other clip advancement mechanism within a clip track, and that any combination of features can be used and positioned at various locations on one or both components.

FIGS. 7-9 illustrate various exemplary components of a clip forming assembly. Referring first to FIG. 7, an exemplary embodiment of the jaws 20 are shown. As previously mentioned, the jaws 20 can include a proximal portion 20 a having teeth 94 for mating with corresponding teeth 78 formed on the jaw retaining shaft 28. Other techniques can, however, be used to mate the jaws 20 to the jaw retaining shaft 28. For example, a dovetail connection, a male-female connection, etc., can be used. Alternatively, the jaws 20 can be integrally formed with the retaining shaft 28. The distal portion 20 b of the jaws 20 can be adapted to receive a clip therebetween, and thus the distal portion 20 b can include first and second opposed jaw members 96 a, 96 b that are movable relative to one another. In an exemplary embodiment, the jaw members 96 a, 96 b are biased to an open position, and a force is required to move the jaw members 96 a, 96 b toward one another. The jaw members 96 a, 96 b can each include a groove (only one groove 97 is shown) formed therein on opposed inner surfaces thereof for receiving the legs of a clip in alignment with the jaw members 96 a, 96 b. The jaws members 96 a, 96 b can also each include a cam track 98 a, 98 b formed therein for allowing the cam 42 to engage the jaw members 96 a, 96 b and move the jaw members 96 a, 96 b toward one another. In an exemplary embodiment, the cam track 98 a, 98 b is formed on a superior surface of the jaw members 96 a, 96 b.

FIG. 8 illustrates an exemplary cam 42 for slidably mating to and engaging the jaw members 96, 96 b. The cam 42 can have a variety of configurations, but in the illustrated embodiment it includes a proximal end 42 a that is adapted to mate to a push rod 44, discussed in more detail below, and a distal end 42 b that is adapted to engage the jaw members 96 a, 96 b. A variety of techniques can be used to mate the cam 42 to the push rod 44, but in the illustrated exemplary embodiment the cam 42 includes a female or keyed cut-out 100 formed therein and adapted to receive a male or key member 102 formed on the distal end 44 b of the push rod 44. The male member 102 is shown in more detail in FIG. 9, which illustrates the push rod 44. As shown, the male member 102 has a shape that corresponds to the shape of the cut-out 100 to allow the two members 42, 44 to mate. A person skilled in the art will appreciate that the cam 42 and the push rod 44 can optionally be integrally formed with one another. The proximal end 44 a of the push rod 44 can be adapted to mate to a closure link assembly, discussed in more detail below, for moving the push rod 44 and the cam 42 relative to the jaws 20.

As is further shown in FIG. 8, the cam 42 can also include a protrusion 42 c formed thereon that is adapted to be slidably received within an elongate slot 20 c formed in the jaws 20. In use, the protrusion 42 c and the slot 20 c can function to form a proximal stop for the clip forming assembly.

Referring back to FIG. 8, the distal end 42 b of the cam 42 can be adapted to engage the jaw members 96 a, 96 b. While a variety of techniques can be used, in the illustrated exemplary embodiment the distal end 42 b includes a camming channel or tapering recess 104 formed therein for slidably receiving the cam tracks 98 a, 98 b on the jaw members 96 a, 96 b. In use, as shown in FIGS. 10A and 10B, the cam 42 can be advanced from a proximal position, in which the jaw members 96 a, 96 b are spaced a distance apart from one another, to a distal position, in which the jaw members 96 a, 96 b are positioned adjacent to one another and in a closed position. As the cam 42 is advanced over the jaw members 96 a, 96 b, the tapering recess 104 will push the jaw members 96 a, 96 b toward one another, thereby crimping a clip disposed therebetween.

As previously mentioned, the surgical clip applier 10 can also include a tissue stop 46 for facilitating positioning of the tissue at the surgical site within jaws 20. FIG. 11A shows one exemplary embodiment of a tissue stop 46 having proximal end and distal ends 46 a, 46 b. The proximal end 46 a can be adapted to mate to a distal end of the clip track 30 for positioning the tissue stop 46 adjacent to the jaws 20. However, the tissue stop 46 can be integrally formed with the clip track 30, or it can be adapted to mate to or be integrally formed with a variety of other components of the shaft 18. The distal end 46 b of the tissue stop 46 can have a shape that is adapted to seat a vessel, duct, shunt, etc. therebetween to position and aligned the jaws 20 relative to the target site. As shown in FIG. 11A the distal end 46 b of the tissue stop 46 is substantially v-shaped. The distal end 46 b can also have a curved configuration to facilitate placement of the device through a trocar or other access tube.

The tissue stop, or other components of the device, can also optionally include features to support and stabilize a clip during clip formation. When a clip is being formed between the jaws, the clip can pivot and become misaligned. In particular, as the jaws are closed, the terminal end of each leg of the clip will be moved toward one another. As a result, the jaws will only engage a bend portion on each leg, thus allowing the terminal ends of the legs and the apex of the clip to swing out of alignment with the jaws, i.e., to pivot vertically relative to the jaws. Further closure of the jaws can thus result in a malformed clip. Accordingly, the device can include features to align and guide the clip into the jaws, and to prevent the clip from pivoting or otherwise becoming misaligned during clip formation.

While the alignment feature can have a variety of configurations, and it can be formed on various components of the device, FIG. 11A illustrates a central tang 47 formed at a mid-portion of the distal end 46 b of the tissue stop 46 for maintaining a clip in alignment with the tip of the advancer assembly 40. In particular, the central tang 47 can allow the apex of a clip to ride therealong thus preventing the clip from becoming misaligned relative to the advancer assembly 40 that is pushing the clip in a distal direction. A person skilled in the art will appreciate that the tissue stop 46 can have a variety of other configurations, and it can include a variety of other features to facilitate advancement of a clip therealong.

FIG. 12A illustrates the tissue stop 46 in use. As shown, the tissue stop 46 is positioned just inferior to the jaws 20 and at a location that allows a vessel, duct, shunt etc. to be received between the jaws 20. As is further shown, a surgical clip 36 is positioned between the jaws 20 such that the bight portion 36 a of the clip 36 is aligned with the tissue stop 46. This will allow the legs 36 b of the clip 36 to be fully positioned around the vessel, duct, shunt, or other target site.

FIGS. 11B-11D illustrate another exemplary embodiment of a tissue stop 46′ having an alignment feature or guide member formed thereon and adapted to align and guide the clip into the jaws, and more preferably to maintain the clip in alignment with the jaws during clip formation. In this embodiment, the alignment feature is in the form of a ramped member 4T extending longitudinally along a central axis of the tissue stop 46′ and protruding above a superior surface of the tissue stop 46′. The ramped member 47′ is preferably rigid, and increases in height from a proximal end 46 a′ to a distal end 46 b′ of the tissue stop 46′. The angle can vary, however, depending on the particular angle of the jaws. The ramp member 47′ preferably terminates just proximal to the tissue-receiving recess 46 c′ formed in the distal tip of the tissue stop 46′. As a result, the ramped member 47′ is positioned just proximal to the jaws 20, thus allowing the ramped member 47′ to guide a clip, as well as the tip of the advancer assembly 40 that is pushing the clip, into the jaws 20 at an appropriate angle. In use, the ramped member 47′ can abut against an inferior surface of the apex of a clip disposed between the jaws 20 to prevent the clip from pivoting vertically as the jaws 20 are closed to form the clip. In particular, when the advancer assembly 40 is moved to the distal-most position along the ramped member 47′, the apex of the clip will abut against the surface of the ramped member 47′. As the clip is compressed between the jaws 20 and the legs of the clip move toward one another, the jaws 20 will only engage a bend portion on each leg. As a result, legs and the apex of the clip are free to pivot vertically. However, since the apex is resting against the superior surface 47 a′ of the ramped member 47′, the ramped member 47′ will prevent the apex from moving vertically in a downward or inferior direction, thereby preventing the legs of the clip from moving vertically in an upward or superior direction, i.e., the ramped member 47′ will prevent the clip from swinging within the jaws 20. Thus, the ramped member 47′ is effective to prevent or limit harmful rotational forces generated when the jaws 20 are closed to form the clip. The clip is thus maintained in alignment with the jaws 20.

A person skilled in the art will appreciate that the shape, size, and configuration of the ramp member can vary depending on the particular configuration of the jaws and other components of the clip applier. In one exemplary embodiment, the ramped member 47′ can have a maximum height h_(Rmax) of about 0.025″, as measured from a central plane extending through the tissue stop 46′. More preferably the height h_(Rmax) is in the range of about 0.008″″ to 0.020″, and most preferably the height h_(Rmax) is in the range of about 0.010″ to 0.015″. The incline angle α_(R) of the ramped member 47′ can also vary, but in an exemplary embodiment the ramped member 47′ has an incline angle α_(R) in the range of about 5° to 45°, and more preferably 5° to 30°, and most preferably 10° to 20°. The width w_(r) of the ramped member 47′ can also vary, but in an exemplary embodiment the ramped member 47′ preferably has a width w_(r) that is slightly less than a space between the jaws 20 in the fully closed position.

FIGS. 11E and 11F illustrate another exemplary embodiment of a tissue stop 46″ having proximal and distal ends 46 a″, 46 b″. The proximal end 46 a″ can be adapted to mate to a distal end of the clip track 30 for positioning the tissue stop 46″ adjacent to the jaws 20. However, in other embodiments the tissue stop 46″ can be integrally formed with the clip track 30, or it can be adapted to mate to or be integrally formed with a variety of other components of the shaft 18. The distal end 46 b″ of the tissue stop 46″ can have a shape that is adapted to seat a vessel, duct, shunt, etc. therebetween to position and align the jaws 20 relative to the target site. For example the tissue stop 46″ can have a V-shape that is defined, at least in part, by first and second arms 39 a, 39 b.

In this embodiment, the tissue stop 46″, also referred to as a guide member or advancer guide, is particularly configured for use with the advancer 40″ shown in FIGS. 5C and 5D. In particular, the tissue stop 46″ includes features to accommodate the increased height of the advancer tip 90″ as previously discussed. As shown in FIGS. 11E and 11F, the tissue stop 46″ can include an opening or channel 49 formed therein and adapted to allow the distal tip 90″ of the advancer 40″ to deflect in an inferior direction, i.e., into or through the channel 49, during movement of the advancer 40″ between proximal and distal positions. While the channel 49 can be located at any position on the tissue stop 46″, in the embodiment the channel 49 is disposed at a central to proximal location longitudinally along the tissue stop 46″. The channel 49 can also be located in a recessed track 46 t formed in a superior surface 46s of the tissue stop 46″, such that the channel 49 is located a distance apart and inferior to the superior surface 46 s. The recessed track 46 t can be in the form on a longitudinally extending cut-out formed along a substantial portion of the tissue stop 46″, so as to create opposed side rails 46 r extending longitudinally along a substantial length of the tissue stop 46″. The guide rails 46 r allow the advancer 40″ to slide there along at a location above the channel 49.

As further shown in FIGS. 11E and 11F, the recessed track 46 t can include a sloped or ramped surface adjacent to proximal and distal ends of the channel 49, such that the channel 49 includes a distal ramp 51 and a proximal ramp 53. The distal ramp 51 can increase in height in the inferior to superior direction from a proximal end to a distal end. The distal ramp 51 can function to deflect the advancer tip 90″ in a superior direction as the advancer 40″ is advanced distally. The proximal ramp 53 can increase in height in the inferior to superior direction from a distal end to a proximal end. The proximal ramp 53 can function to deflect the advancer tip 90″ in a superior direction as the advancer 40″ is advanced proximally.

As further shown in FIGS. 11E and 11F, the tissue stop 46″ can also include a longitudinally-extending groove 55 located distal to the channel 49 and adjacent to the distal end. The groove 55 can extend along the longitudinal axis of the tissue stop 46″ in a substantially central location laterally between the first and second arms 39 a, 39 b and it can be positioned substantially directly in line with the channel 49 such that the distal tip 90″ traveling distally up the distal ramp 51 and out of the channel 49 can continue traveling in a straight line along the groove 55 to move a clip over the tissue stop 46″. In other words, the groove 55 substantially prevents the distal tip 90″ from moving laterally relative to opposed lateral sides of the tissue stop 46″ to keep the tip 90″ in alignment with the apex of the clip. In some embodiments, the groove 55 can be recessed below a top surface of the first and second arms 39 a, 39 b to accommodate the increased height H of the distal tip 90″. Since an apex of a clip generally travels a distance above the tissue stop 46″, this allows a height H of a distal tip 90″ to extend both above and below the apex of the clip.

As noted above, when the clip is pushed into the jaws 20, the clip must reorient itself to accommodate the angle of the jaws 20. This reorientation can cause an apex of the clip to drop vertically or rotate downward (in an inferior direction) relative to the opposed legs of the clip. This drop may prevent the clip from being positioned properly within the jaws 20. For example, in some cases, the apex of the clip may drop below a distal end of the clip-pusher member such that the clip-pusher member bypasses the clip and moves over top of its apex. The clip-pusher member would then be unable to properly position the clip within the jaws 20. The height H of the clip-pusher member 90″ in the embodiment shown in FIGS. 5C and 5D, however, in combination with the groove 55 in the tissue stop 46″ in the embodiment shown in FIGS. 11E and 11F, provides a solid surface against which the apex of the clip can move if it pivots in the superior and/or inferior directions. If the apex of the clip drops as it is being pushed into the jaws 20, the distal facing surface 41 of the distal tip 90″ can provide a solid surface that extends down into the recessed groove 55, thereby preventing the apex of the clip from slipping beneath the distal tip 90″. In this way, an apex of a clip cannot fall below an inferior surface of the distal facing surface 41, thereby allowing the clip to always maintain contact with the distal tip 90″ and thus to always be positioned properly within the jaws 20.

FIGS. 12B-12E illustrate an exemplary interaction between the tissue stop 46″ and the distal tip 90″ in more detail. In FIG. 12B, the distal tip 90″ is near the beginning of a clip forming cycle. The distal tip 90″ is shown pushing the distal-most clip C into the jaws 20. The next clip C₁ can be at a distal position in the clip track 30. As shown, the distal-facing surface 41 of the distal tip 90″ is abutting an apex of the clip C and it has a height H that is substantially greater than a height of the apex. The distal-facing surface 41 of the distal tip 90″ can travel within the groove 55 of the tissue stop 46″ as it pushes the clip C into the jaws 20. In this way, as the legs of the clip C rotate upward (in a superior direction) slightly to enter the jaws 20, the apex of the clip C will always abut against the distal-facing surface 41, even if the apex pivots downward in the inferior direction. More particularly, the inferior surface of the distal tip 90″ is in contact with the groove 55, and thus the apex of the clip C will never fall below the inferior surface of the distal tip 90″. In this way, the distal-facing surface 41 is able to maintain contact with the apex of the clip C at all times and is therefore able to position the clip C properly within the jaws 20. The distal-facing surface 41 can also maintain contact with the apex of the clip C at all times during forming of the clip C between the jaws 20 to ensure that the clip C does not move proximally.

As illustrated in FIG. 12C, once the clip C is formed within the jaws 20 and released, the distal tip 90″ begins moving proximally from its distal-most position within the groove 55 in order to position itself behind or proximal to the next clip C₁. At this point in the clip forming cycle, the distal tip 90″ is positioned distal to the next clip C₁, and the highest point on the superior surface 47 of the distal tip 90″ is at substantially the same height as the superior surface of the clip C₁. Therefore, as the distal tip 90″ moves proximally into contact with the clip C₁, the superior surface 47 of the distal tip 90″ can contact an inferior surface of an apex of the clip C₁. Since the clip C₁ is rigidly held within the clip track 30, the clip C₁ produces a downward force on the distal tip 90″ to deflect the resilient distal tip 90″ downward. As the clip C₁ and the superior surface 47 of the distal tip 90″ contact one another, the distal tip 90″ is traveling toward the distal ramp 51. Thus, the downward force applied by the clip C₁ can cause the distal tip 90″ to deflect downward in an inferior direction such that the distal biasing surface 43 of the distal tip 90″ travels down the distal ramp 51 and into or partially through the channel 49. With the distal tip 90″ traveling proximally in the channel 49, its superior surface 47 is lower than an inferior surface of the apex of the clip C₁ and can thus travel proximally under the inferior surface of the apex of the clip C₁, as shown most clearly in FIG. 12D.

As the distal tip 90″ continues to move proximally within the channel 49, the distal-facing surface 41 moves proximal to the apex of the clip C₁. As it moves proximally, the proximal biasing surface 45 contacts the proximal ramp 53 and begins to move up the proximal ramp 53. Since the superior surface 47 of the distal tip 90″ is no longer in contact with the inferior surface of the clip C₁, when the proximal biasing surface 45 travels up the proximal ramp 53, the distal tip 90″ deflects back up in a superior direction such that it is of a substantially even height with the apex of the clip C₁ once again, as shown most clearly in FIG. 12E. The distal tip 90″ is now in its proximal-most position and is ready to begin the clip forming cycle over again. Thus, as the advancer 40″, and hence the distal tip 90″, are moved distally, the distal biasing surface 43 on the distal tip 90″ will travel distally along the distal ramp 51 to cause the distal tip 90″ to deflect upward in the superior direction, thus ensuring that contact is maintained between the apex of the clip and the distal-facing surface 41 of the distal tip 90″.

FIGS. 13-26B illustrate various exemplary internal components of the housing 12 for controlling clip advancement and forming. As previously discussed, the surgical clip applier 10 can include some or all of the features disclosed herein, and it can include a variety of other features known in the art. In certain exemplary embodiments, the internal components of the clip applier 10 can include a clip advancing assembly, that couples to the clip advancing assembly of the shaft 18, for advancing at least one clip through the elongate shaft 18 to position the clip between the jaws 20, and a clip forming assembly, that couples to the clip forming assembly of the shaft 18, for closing the jaws 20 to form a partially or fully closed clip. Other exemplary features include an anti-backup mechanism for controlling movement of the trigger 16, an overload mechanism for preventing overload of the force applied to the jaws 20 by the clip forming assembly, and a clip quantity indicator for indicating a quantity of clips remaining in the device 10.

FIGS. 13-16D illustrate an exemplary embodiment of a clip advancing assembly of the housing 12 for effecting movement of the feed bar 38 within the shaft 18. In general, the clip advancing assembly can include a trigger insert 48 that is coupled to the trigger 16, a feed bar coupler 50 that can mate to a proximal end 38 a of the feed bar 38, and a feed link 52 that is adapted to extend between the trigger insert 48 and the feed bar coupler 50 for transferring motion from the trigger insert 48 to the feed bar coupler 50.

FIG. 14 illustrates the trigger insert 48 in more detail. The shape of the trigger insert 48 can vary depending on the other components of the housing 12, but in the illustrated embodiment the trigger insert 48 includes a central portion 48 a that is adapted to pivotally mate to the housing 12, and an elongate portion 48 b that is adapted to extend into and mate to the trigger 16. The central portion 48 a can include a bore 106 extending therethrough for receiving a shaft for pivotally mating the trigger insert 48 to the housing 12. The central portion 48 a can also include a first recess 108 formed in a superior side edge for receiving a portion of the feed link 52. The first recess 108 preferably has a size and shape that allows a portion of the feed link 52 to extend therein such that the feed link 52 will be forced to pivot when the trigger insert 48 pivots due to movement of the trigger 16. As shown in FIG. 14, the first recess 108 is substantially elongate and includes a substantially circular portion formed therein for seating a shaft formed on a proximal end of the feed link 52, as will be discussed in more detail with respect to FIG. 16. The trigger insert 48 can also include a second recess 110 formed in a back side edge for receiving a closure link roller 54 that is coupled to the push bar 44 for moving the cam 42 to close the jaws 20, and ratchet teeth 112 formed on the bottom side edge thereof for mating with a pawl 60 for controlling movement of the trigger 16, as will be discussed in more detail below.

The exemplary feed bar coupler 50 is shown in more detail in FIGS. 15A and 15B, and it can be adapted to couple the proximal end of the feed bar 38 to the distal end of the feed link 52. While a variety of techniques can be used to mate the feed bar coupler 50 to the proximal end 38 a of the feed bar 38, in an exemplary embodiment the feed bar coupler 50 is formed from two separate halves 50 a, 50 b that mate together to maintain the proximal end 38 a of the feed bar 38 therebetween. When mated, the two halves 50 a, 50 b together define a central shaft 50 c having substantially circular flanges 50 d, 50 e formed on opposed ends thereof and defining a recess 50 f therebetween for seating a distal portion of the feed link 52. The central shaft 50 c defines a lumen 50 g therethrough for receiving the proximal end 38 a of the feed bar 38 and for locking the feed bar 38 in a substantially fixed position relative to the feed bar coupler 50. The feed bar coupler 50 can, however, be integrally formed with the feed bar 38, and it can have a variety of other shapes and sizes to facilitate mating with the feed link 52.

FIG. 16 illustrates an exemplary feed link 52, which can extend between the trigger insert 48 and the feed bar coupler 52. In general, the feed link 52 can have a substantially planar elongate shape with proximal and distal ends 52 a, 52 b. The proximal end 52 a is adapted to rotatably sit within the first recess 108 of the trigger insert 48 and thus, as previously discussed, it can include a shaft 53 (FIG. 1B) extending therethrough. The shaft 53 can be adapted to pivotally rotate within the first recess 108 of the trigger insert 48, thereby allowing the trigger insert 48 to pivot the feed link 52. The distal end 52 b of the feed link 52 can be adapted to couple to feed bar coupler 50 and thus, in an exemplary embodiment, it includes opposed arms 114 a, 114 b formed thereon and defining an opening 116 therebetween for seating the central shaft 50 a of the feed bar coupler 50. The arms 114 a, 114 b are effective to engage and move the coupler 50 as the feed link 52 pivots about a pivot axis X. The pivot axis X can be defined by the location at which the feed link 52 couples to the housing 12, and it can be positioned anywhere on the feed link 52, but in the illustrated embodiment it is positioned adjacent to the proximal end 52 a of the feed link 52.

In an exemplary embodiment, the feed link 52 can be flexible to eliminate the need to calibrate the clip advancing assembly and the clip forming assembly. In particular, the feed link 52 allows the trigger 16 to continue moving toward a closed position even after the feed bar 38 and feed bar coupler 50 are in a distal-most position, and it provides some freedom to the clip forming and clip advancing assemblies. In other words, the trigger 16 is pliant relative to the feed bar 38 during closure of the trigger.

The particular stiffness and strength of the feed link 52 can vary depending on the configuration of the clip advancing assembly and the clip forming assembly, but in one exemplary embodiment the feed link 52 has a stiffness that is in the range of 75 to 110 lbs per inch, and more preferably that is about 93 lbs per inch (as measured at the interface between the link 52 and the feed bar coupler 50), and it has a strength of that is in the range of 25 lbs and 50 lbs, and more preferably that is about 35 lbs. The feed link 52 can also be formed from a variety of materials, including a variety of polymers, metals, etc. One exemplary material is a glass-reinforced polyetherimide, but a number of reinforced thermoplastics could be used, including glass reinforced liquid-crystal polymers, glass-reinforced nylons, and carbon-fiber reinforced versions of these and similar thermoplastics. Fiber-reinforced thermoset polymers such as thermoset polyesters could also be used. Feed link 52 could also be fabricated from a metal, such as spring steel to achieve the desired combination of limited flexibility and controlled strength.

FIGS. 17A-17D illustrate the exemplary clip advancing assembly in use. FIG. 17A shows an initial position, wherein the trigger 16 is resting in an open position, the feed bar coupler 50 and feed bar 38 are in a proximal-most position, and the feed link 52 extends between the trigger insert 48 and the feed bar coupler 50. As previously discussed, in the initial open position the protrusion 86 on the feed bar 38 in positioned in the proximal end of the elongate slot 88 in the jaw retainer shaft 28. A first biasing member, e.g., spring 120, is coupled to the trigger insert 48 and the housing 12 to maintain the trigger insert 48 and trigger 16 in the open position, and a second biasing member, e.g., spring 122, extends between a shaft coupler 124, which rotatably mates the shaft 18 to the housing 12, and the feed bar coupler 50 to maintain the feed bar coupler 50 and feed bar 38 in the proximal-most position.

When the trigger 16 is actuated and moved toward the closed position, i.e., toward the stationary handle 14, to overcome the biasing forces applied by the springs 120, 122, the trigger insert 48 begins to pivot in a counter-clockwise direction, as shown in FIG. 17B. As a result, the feed link 52 is forced to pivot in a counter-clockwise direction, thereby moving the feed bar coupler 50 and feed bar 38 in a distal direction. The protrusion 86 on the feed bar 38 thus moves distally within the elongate slot 88 in the jaw retainer shaft 28, thereby advancing the feeder shoe 34 and the clips 36 disposed within the clip track. Spring 120 is extended between the housing and the trigger insert 48, and spring 122 is compressed between the feed bar coupler 50 and the shaft coupler 124.

As the trigger 16 is further actuated and the trigger insert 48 continues to pivot, the feed bar coupler 50 and feed bar 38 will eventually reach a distal-most position. In this position, the protrusion 86 on the feed bar 38 will be positioned at the distal end of the slot 88 in the jaw retainer shaft 28 and a clip will be positioned between the jaws 20, as previously discussed. Spring 122 will be fully compressed between the shaft coupler 124 and the feed bar coupler 50, and the feed link 52 will flex, as shown in FIGS. 17C and 17D. As the feed link 52 flexes, and more preferably once the feed link 52 fully flexed, the clip forming assembly will be actuated to close the jaws 20. The feed link 52 will remain flexed during actuation of the clip forming assembly, e.g., the second stage of actuation, such that the trigger insert 48 is pliant relative to the clip advancing assembly, and in particular the feed bar 38.

An exemplary clip forming assembly of the housing 12 is shown in more detail in FIGS. 18-20. In general, the clip forming assembly is disposed within the housing 12 and it is effective to move the push rod 44 and cam 42 relative to the jaws 20 to move the jaws 20 to a closed position and thereby crimp a clip positioned therebetween. While the clip forming assembly can have a variety of configurations, the illustrated exemplary clip forming assembly includes a closure link roller 54 that is slidably coupled to the trigger insert 48, a closure link 56 that is adapted to couple to the closure link roller 54, and a closure coupler 58 that is adapted to couple to the closure link 56 and to the push rod 44.

FIG. 18 illustrates the closure link roller 54 in more detail and, as shown, the closure link roller 54 includes a central shaft 54 a having substantially circular flanges 54 b, 54 c formed adjacent to the opposed terminal ends thereof. The central shaft 54 a can be adapted to sit within the second recess 110 in the trigger insert 48 such that the flanges 54 b, 54 c are received on opposed sides of the trigger insert 48. The central shaft 54 a can also be adapted to mate to opposed arms 126 a, 126 b of the closure link 56 to position the arms on opposed sides of the trigger insert 48.

An exemplary embodiment of a closure link 56 is shown in more detail in FIG. 19, and as shown it has opposed arms 126 a, 126 b that are spaced a distance apart from one another. Each arm 126 a, 126 b includes a proximal end 128 a, 128 b that is adapted to engage the central shaft 54 a of the closure link roller 54, and a distal end 130 a, 130 b that is adapted to mate to a closure coupler 58 for coupling the closure link roller 54 and closure link 56 to the push rod 44. In an exemplary embodiment, the proximal end 128 a, 128 b of each arm 126 a, 126 b is adapted to pivotally mate to the closure link roller 54, and thus the arms 126 a, 126 b can include, for example, hook-shaped members 132 a, 132 b formed thereon for engaging the central shaft 54 a. The hook-shaped members 132 a, 132 b extend in opposite directions to facilitate engagement between the closure link 56 and the closure link roller 54. The distal end 130 a, 130 b of the arms 126 a, 126 b can be mated to one another, and they can include a lumen 134 extending therethrough for receiving a shaft that is adapted to pivotally mate the closure link 56 to the closure coupler 58. A person skilled in the art will appreciate that a variety of other techniques can be used to mate the closure link 56 to the closure link roller 54 and the closure coupler 58.

An exemplary closure coupler 58 is shown in more detail in FIG. 20A, and as shown it includes a proximal portion 58 a having two arms 136 a, 136 b with lumens 138 a, 138 b extending therethrough and adapted to be aligned with the lumen 134 in the closure link 56 for receiving a shaft to mate the two components. The closure coupler 58 can also include a distal portion 58 b that is adapted to mate to the proximal end 44 a of the push rod 44 (FIG. 9). In an exemplary embodiment, the closure coupler 58 includes a cut-out 59 (FIGS. 20B and 20C) formed therein and having a shape that is adapted to seat the proximal end 44 a of the push rod 44. The distal portion 58 b of the closure coupler 58 can also be configured to receive a portion of the feed bar coupler 50 when the trigger 16 is in the open position. A person skilled in the art will appreciate that a variety of other mating techniques can be used to mate the closure coupler 58 to the push rod 44, and that the closure coupler 58 and the push rod 44 can optionally be integrally formed with one another.

In other exemplary embodiments, a preloaded joint can be formed between the push rod 44 and the closure coupler 58 to prevent accidental release of a clip from the jaws, particularly during the early stages of closure, if the user eases-up on the trigger 16. In particular, while the anti-backup mechanism, discussed in more detail below, can be adapted to prevent the trigger 16 from opening until the trigger 16 reaches a predetermined position, the anti-backup mechanism may allow some minor movement of the trigger 16. Thus, in the event a user eases-up on the trigger 16 and minor opening of the trigger 16 occurs, the preloaded joint will bias the push rod 44 in a distal direction, thereby maintaining the push rod 44 in a substantially fixed position, while allowing the closure coupler 58 to move proximally until the trigger 16 is engaged by the anti-backup mechanism.

While the preloaded joint can have a variety of configurations, and it can be positioned at various locations along the clip forming assembly, in one exemplary embodiment the preloaded joint can be in the form of a biasing member disposed within the cut-out 59 to bias the push rod 44 in a distal direction. While a variety of biasing members can be used, in the embodiment shown in FIG. 20B, the biasing member is a cantilevered beam 61 that is positioned between the proximal end 44 a of the push rod 44 and the back wall of the recess 59 to bias the push rod 44 distally. The cantilevered beam 61 can be formed from a shape memory material, such as Nitinol, that allows the beam 61 to flex or flatten when a proximally-directed force is applied thereto. The beam 61 can also be formed from a variety of other materials, such as spring steel or reinforced polymers, and more than one beam can be used. FIG. 20C illustrates another embodiment of a biasing member which is in the form of a coil or other type of spring 63. As shown, the spring 63 is disposed between the proximal end 44 a of the push rod 44 and the back wall of the recess 59 to bias the push rod 44 distally. The spring 63 is adapted to compress when a proximally-directed force is applied thereto. A person skilled in the art will appreciate that a variety of other biasing members can be used, including elastomeric compression members.

The preloaded joint can also optionally include features to enhance performance of the cantilevered beam or spring during the clip forming process. In the embodiment shown in FIG. 20B, the load of the cantilevered beam 61 remains primarily uniform as the cantilevered beam is compressed during closure, however the load increases significantly during the final stages of closure. This is illustrated in FIG. 20D, which shows a graph of the load/displacement curve of the cantilevered beam 61 shown in FIG. 20B. The left end of the curve represents the unloaded height of the cantilevered beam 61, while the right end of the curve represents the point at which the cantilevered beam 61 is fully compressed or flattened. The upper curve represents the force resulting as the cantilevered beam 61 is compressed during a typical closing stroke, with the exception that the force is measured from a free state of the cantilevered beam 61 whereas the cantilevered beam 61 is initially partially compressed when it is disposed within the closure coupler 58. As shown, the load remains substantially constant (excluding the initial compression stages), increasing only slightly during the closing stroke as the cantilevered beam 61 is being compressed. However, the load increases significantly at the final stages of closure when the cantilevered beam 61 is fully flattened. This is due to deflection of the cantilevered beam 61 which causes the load to be transferred from the terminal ends of the cantilevered beam 61 inward. As the cantilevered beam 61 deflects and the load is transferred inward, the effective length of the cantilevered beam 61 is decreased, thereby increasing the load. In order to prevent this, the preloaded joint can optionally include features to enhance the cantilevered beam or spring performance, and in particular to maintain a substantially constant load during clip formation.

FIG. 20E illustrates one exemplary embodiment of a technique for enhancing the cantilevered beam or spring performance. As shown, the recess 59′ in the closure coupler 58′ includes two ridges 59 a′, 59 b′ formed therein on the back surface thereof such that the ridges 59 a′, 59 b′ are positioned underneath or behind the cantilevered beam (not shown). The ridges 59 a′, 59 b′ are spaced a distance apart from one another and each ridge 59 a′, 59 b′ has a height of at least about 0.005″ to prevent the cantilevered beam from fully flattening against the back surface of the recess. As a result, the ridges 59 a′, 59 b′ will prevent the cantilevered beam from deflecting, thereby preventing the load of the spring or cantilevered beam from transferring from the terminal ends inward. A person skilled in the art will appreciate that the particular location, quantity, and size of the ridges 59 a′, 59 b′ can vary depending on the configuration of the preloaded joint, as well as the forces necessary to prevent clip fallout during closure.

In use, referring back to FIGS. 17A-17D, as the trigger 16 is initially moved from the open position toward the closed position, the closure link roller 54 will roll within the recess 110 in the trigger insert 48. Once the feed bar 38 and feed bar coupler 50 are in the distal-most position, as shown in FIG. 17C, further actuation of the trigger 16 will cause the recess 110 in the trigger insert 48 to engage the closure link roller 54 forcing it to pivot with the trigger insert 48, as shown in FIG. 17D. As a result, the closure coupler 58 will move distally, thereby causing the push rod 44 to move distally. As the push rod 44 advances distally, the cam 42 is advanced over the jaws 20 to close the jaws 20 and crimp the clip positioned therebetween. The trigger 16 can optionally be partially closed to only partially close the jaws 20 and thus partially crimp a clip disposed therebetween. Exemplary techniques for facilitating selective full and partial closure of the clip will be discussed in more detail below. Once the clip is applied, the trigger 16 can be released thereby allowing spring 120 to pull the trigger insert 48 back to its initial position, and allowing spring 122 to force the feed bar coupler 50 and feed bar 38 back to the proximal position. As the trigger insert 48 returns to its initial position, the closure link roller 54 is moved back to its initial position as well, thereby pulling the closure link 56, closure coupler 58, and push bar 44 proximally.

The surgical clip applier 10 can also include a variety of other features to facilitate use of the device 10. In one exemplary embodiment, the surgical clip applier 10 can include an anti-backup mechanism for controlling movement of the trigger 16. In particular, the anti-backup mechanism can prevent the trigger 16 from opening during a partial closing stroke. However, once the trigger reaches a predetermined position, at which point the clip positioned between the jaws can be partially crimped, the anti-backup mechanism can release the trigger allowing the trigger to open and release the clip or to close to fully crimp the clip, as may be desired by the user.

FIGS. 21A and 21B illustrate one exemplary embodiment of an anti-backup mechanism in the form of a ratchet. As shown, the ratchet includes a set of teeth 112 formed on the trigger insert 48, and a pawl 60 that is adapted to be rotatably disposed within the housing 12 and positioned adjacent to the trigger insert 48 such that closure of the trigger 16 and pivotal movement of the trigger insert 48 will cause the pawl 60 to engage the teeth 112. The teeth 112 can be configured to prevent rotation of the pawl 60 until the pawl 60 reaches a predetermined position, at which point the pawl 60 is free to rotate, thereby allowing the trigger 16 to open or close. The predetermined position preferably corresponds to a position at which the jaws 20 are partially closed. In an exemplary embodiment, as shown, the teeth 112 include a first set of teeth 112 a, e.g., ten teeth, having a size that prevents rotation of the pawl 60 relative thereto, thus preventing the trigger 16 from opening when the pawl 60 is engaged with the first set 112 a of teeth 112. The teeth 112 can also include a final or terminal tooth, referred to as a tock tooth 112 b, that has a size that allows the pawl 60 to rotate relative thereto when the pawl 60 is engaged with the tock tooth 112 b. In particular, the tock tooth 112 b preferably has a size that is substantially greater than the size of the first set of teeth 112 a such that a relatively large notch 140 is formed between the first set of teeth 112 a and the tock tooth 112 b. The notch 140 has a size that allows the pawl 60 to pivot therein, thus allowing the pawl 60 to be selectively moved beyond the tock tooth 112 b or back toward the first set of teeth 112 a. A person skilled in the art will appreciate that the tock tooth 112 b can have the same size or a smaller size than the first ten teeth 112 a while still providing a notch 140 formed therebetween that allows the pawl 60 to pivot therein.

FIGS. 22A-22D illustrates the ratchet mechanism in use. When the trigger 16 is initially moved toward a closed position, as shown in FIG. 22A, the pawl 60 will engage the first set of teeth 112 a thereby preventing the trigger 16 from opening. Further actuation of the trigger 16 will cause the pawl 60 to advance past the first set of teeth 112 a until the pawl 60 reaches the notch 140 next to the tock tooth 112 b. Once the pawl 60 reaches the tock tooth 112 b, at which point the jaws 20 are partially closed due the partial distal movement of the cam 42 over the jaws 20, the pawl 60 is free to rotate thereby allowing the trigger 16 to open or close, as may be desired by the user. FIG. 22C illustrates the trigger 16 in a fully-closed position, and FIGS. 22D and 22E illustrate the trigger 16 returning to the open position.

The ratchet mechanism can also be configured to emit an audible sound that indicates the position of the jaws 20. For example, a first sound can be emitted when the pawl 60 engages the first set of teeth 112 a, and a second, different sound, e.g., a louder sound, can be emitted when the pawl 60 engages the tock tooth 112 b. As a result, when the trigger 16 reaches the predetermined position at which the pawl 60 is engaged with the tock tooth 112 b, the sound indicates to the user that the jaws 20 are in the partially closed position. The user can thus release the trigger 16 to release a partially closed clip, or they can fully close the trigger 16 to fully close the clip.

In another exemplary embodiment, the surgical clip applier 10 can include an overload mechanism that is adapted to prevent overload of a force applied to the jaws 20 by the trigger 16. Typically, during application of a surgical clip, a certain force is required to close the jaws 20 and crimp the clip around the tissue positioned therebetween. As the forming process proceeds and the clip is at least partially closed, the force required to continue closing the jaws 20 around the clip significantly increases. Accordingly, in an exemplary embodiment, the overload mechanism can have a resistance that correlates to the force required to close the jaws 20. In other words, the resistance of the overload mechanism can increase as the force required to close the jaws 20 increases. The resistance is, however, preferably slightly greater than the force required to close the jaws 20 to prevent accidental actuation of the overload mechanism. As a result, if the jaws 20 are prevented from closing when the trigger 16 is initially actuated, the force required to overcome the resistance of the overload mechanism is relatively low. This is particularly advantageous as the jaws 20 are more susceptible to being deformed when they are open or only partially closed. The overload mechanism will actuate more readily in the early stages of clip formation to prevent deformation of the jaws. Conversely, when the jaws 20 are substantially closed, the resistance is relatively high such that the overload mechanism can only be actuated upon application of a significant force applied to the jaws 20.

One exemplary embodiment of an overload mechanism is provided. In general, the overload mechanism can include an overload housing formed from two halves and containing a profile link, a toggle link, a pivot link, and a biasing assembly. The biasing assembly can include a spring post that is coupled to the housing and that includes a bore extending therethrough for receiving a plunger. A spring can be disposed around the spring post, and the plunger can extend through the spring post and includes a head formed thereon that is adapted to abut against the spring. The pivot link can be generally L-shaped and it can be coupled to the housing by a pivot pin extending therethrough. A proximal end of the pivot link can contact the head of the plunger, and a distal end of the pivot link can be pivotally coupled to the toggle link by a pivot pin. The toggle link, in turn, can be coupled to the profile link, which can be slidably and pivotally positioned within the housing adjacent to an opening formed in the housing. Pivotal movement of the profile link within the housing can be achieved by, for example, a pivot pin that extends through the profile link and is that disposed within a first slot (only one slot is shown) formed in each half of the housing, and slidable movement of the profile link within the housing can be achieved by, for example, opposed protrusions formed on the profile link that are received within a second slot (only one slot is shown) formed in each half of the housing.

In use, the profile link can be adapted to receive a force from the clip forming assembly and to counter the force with the resistance of the biasing assembly. In particular, the overload mechanism uses the spring along with the toggle link and pivot link to bias the profile link from either rotating about the pivot pin or sliding against the housing. For the rotational aspect, the force exerted by the compressed spring is transferred through the toggle link and pivot link, such that a rotational moment is applied to the profile link against the housing. Thus this assembly causes the profile link to resist rotation with respect to the housing. If the moment generated by a radial load from the closure link roller against the profile link exceeds the moment of the pivot link and toggle link, the profile link begins to rotate, buckling the toggle link and causing the pivot link to further compress the spring. For the sliding aspect, the pivot link, toggle link, and profile link are aligned such that the sliding force (resistance to slide) is the force required to buckle the toggle link and pivot link. If the radial load from the closure link roller against the profile link exceeds the buckling force of the linkages, then the pivot link further compresses the spring as the profile link slides proximally.

The opening in the housing allows the closure link roller of the clip forming assembly to roll against the profile link. As a result, when the trigger 16 is actuated and moved toward the closed position, the closure link roller applies a force to the profile link. The resistance of the overload spring will, however, maintain the profile link in a substantially fixed position unless the force applied by the closure link roller increases to a force that is greater than the resistance, e.g., a threshold force. This can be caused by, for example, a foreign object positioned between the jaws 20 or when the jaws 20 are fully closed with the clip and vessel, duct, shunt, etc. therebetween. When the jaws 20 cannot be further closed, the force applied to the closure link roller from the closing motion of the trigger 16 will be transferred to the profile link, which will then pivot and slide within the housing, thereby causing the pivot link to pivot, which forces the plunger to compress the overload spring.

As previously noted, the force required to actuate the overload mechanism can correlate to the force required to close the jaws 20, which increases as the trigger 16 is moved to the closed position. This can be achieved due to the configuration of the profile link. In particular, when the closure link roller first comes into contact with the profile link and is thus in a lower position, the profile link can pivot within the housing. As the closure link roller moves upward along the profile link, the force required to overcome the resistance of the overload mechanism increases because the profile link must slide within the housing. The force required to pivot the profile link can be less than the force required to slide the profile link. Accordingly, if the jaws 20 are prevented from being closed, e.g., by a foreign object, as the trigger is initially actuated, a minimal force will be required to cause the closure link roller to transfer the force to the lower portion of the profile link causing the profile link to pivot. When the jaws 20 are substantially closed and the trigger 16 is almost fully actuated, a significant amount of force is required to cause the closure link roller to transfer the force to the upper portion of the profile link causing the profile link to slide within the housing to overcome the resistance of the overload spring. While the amount of force required to actuate the overload mechanism can be greater than and can increase relative to the amount of force required to close the jaws 20, the force is preferably only slightly greater than the force required to close the jaws 20 to prevent deformation or other damage to the jaws 20. A person skilled in the art will appreciate that the resistance can be adjusted based on the force necessary to close the jaws 20.

The profile link, and in particular the distal-facing surface of the profile link, can also have a shape that facilitates correlation between the force required to actuate the overload mechanism and the force required to close the jaws 20. For example, where the force required to close the jaws 20 increases at a linear rate, the distal-facing surface of the profile link can be planar to prevent the profile link from interfering with movement of the closure link roller there over, and to allow a linear force to be applied to the trigger 16 to close the jaws 20. Conversely, where the force required to close the jaws 20 is non-linear as the trigger 16 is moved to the closed position, the profile link can have a non-linear shape that corresponds to the non-linear force. Such a configuration will prevent the forces required to close the cam 42 (FIG. 8) from becoming too high.

By way of non-limiting example, the force required to close the jaws 20 can be non-linear due to the shape of the recess in the cam 42 that is adapted to push the jaw members toward one another. As shown in FIG. 8, the recess 104 can have a curved configuration such that the force will vary as the cam 42 passes over the jaw members 96 a, 96 b. The profile link can therefore having a corresponding curved distal-facing surface such that the force will also vary as the closure link roller passes there over. The profile link is curved such that the lower portion of the profile link is substantially convex and the upper portion of the profile link is substantially concave. A person skilled in the art will appreciate that the profile link can have a variety of other shapes, and that a variety of other techniques can be used to optimize the force necessary to close the jaws 20 and the force necessary to actuate the overload mechanism.

A person skilled in the art will also appreciate that the overload mechanism can have a variety of other configurations. By way of non-limiting example, an overload mechanism is provided in the form of a cantilevered beam for receiving a force applied by the closure link roller. The beam can have a substantially curved member with a bracket coupled to one end thereof The curved member can have a bending moment that, when loaded with a force greater then the bending moment, buckles to assume a low rigidity condition. The bracket can provide more rigidity to the curved member such that the bending moment increases adjacent to the bracket. In use, the beam can be loaded within the housing 12 of the clip applier 10 such that the closure link roller contacts the concave surface, and the beam can be positioned at an angle such that the closure link roller is farther away from the beam when the trigger 16 is initially actuated, and the closure link roller becomes closer to the beam as the trigger 16 moves to the closed position. As a result, the resistance to buckling will increase as the closure link roller moves thereof and the trigger 16 of the clip applier is moved to the closed position. Although not shown, multiple beams could optionally be used in a stacked fashion and the terminal or free end of the beam(s) could be contoured to tailor the buckling load at a particular point along the length of the beam.

In another exemplary embodiment, the surgical clip applier 10 can include a clip quantity indicator for indicating the number of clips remaining in the device 10. While various techniques can be used to indicate the quantity of clips remaining, a clip quantity indicator can have an indicator wheel and an indicator actuator.

The indicator wheel can have a generally circular or cylindrical shape that defines a central axis Y about which the wheel is adapted to rotate. The wheel includes teeth formed therearound and adapted to be engaged by the indicator actuator, and an indicator member. The indicator member can have a variety of configurations, but in an exemplary embodiment the indicator member is in the form of a contrasting color pad having a color, e.g., orange, red, etc., that differs from the remainder of the indicator wheel.

The actuator can be adapted to be slidably disposed within the housing 12 and to couple to the feed link coupler 50 and move as the feed bar coupler 50 and feed bar 38 are moved. Accordingly, the indicator actuator can include a protrusion, only a portion of which is shown, formed on an inferior surface thereof for extending into the recess 50 f formed between the circular flanges 50 d, 50 e on the feed bar coupler 50. The protrusion allows the indicator actuator to be engaged by the feed bar coupler 50 and moved therewith. The indicator actuator can also include an engagement mechanism formed thereon and adapted to engage the teeth formed on the indicator wheel. The engagement mechanism on the indicator actuator can be in the form of an arm having a tab formed on the end thereof for engaging the teeth.

In use, the indicator wheel can be rotatably disposed within the housing 12, and the indicator actuator can be slidably disposed within the housing 12 such that the engagement mechanism is positioned adjacent to the indicator wheel and the protrusion extends into the feed bar coupler 50. The housing 12 includes a window formed therein for providing visual access to the indicator wheel. As the trigger 16 is moved to the closed position and the feed bar coupler 50 is moved distally, the indicator actuator will move distally with the feed bar 38 and feed bar coupler 50. As a result, the engagement mechanism on the indicator actuator will engage the teeth on the indicator wheel, thereby causing the wheel to rotate as a clip is advanced into the jaws 20. Each time the trigger 16 is actuated to advance a clip 20 into the jaws 20, the indicator actuator rotates the indicator wheel. When the clip supply has two or three clips left, the contrasting color pad on the indicator wheel will begin to appear in the window formed in the housing 12, thereby indicating to the user that only a few clips remain. The contrasting color pad can be adapted to occupy the entire window when the clip supply is depleted.

In another exemplary embodiment, the indicator wheel can include an anti-backup mechanism that is adapted to prevent the indicator wheel from rotating in a reverse direction, e.g., a counter-clockwise direction, after being advanced. While the anti-backup mechanism can have a variety of configurations, the indicator wheel can include opposed arms that extend substantially parallel to the axis Y. Each arm can have a pawl formed on a distal-most end thereof that is adapted to engage corresponding teeth formed on the housing 12. While not shown, the corresponding teeth can be formed within a circular protrusion formed on an inner portion of the housing 12 adjacent to the window. When the indicator wheel is disposed within the housing 12, the arms extend into the circular protrusion formed around the inner circumference thereof. As a clip is applied and the indicator wheel is rotated, the arms can deflect over the teeth in the housing to move to the next position. When the indicator actuator slides proximally to return to its initial position, the arms will engage the teeth in the housing to prevent the indicator wheel from rotating in a reverse direction, i.e., returning to the previous position. A person skilled in the art will appreciate that a variety of other techniques can be used to prevent backup of the indicator wheel.

As previously mentioned, the surgical clip applier 10 can be used to apply a partially or fully closed clip to a surgical site, such as a vessel, duct, shunt, etc. In laparoscopic and endoscopic surgery, a small incision is made in the patient's body to provide access to a surgical site. A cannula or access port is typically used to define a working channel extending from the skin incision to the surgical site. Often during surgical procedures it is necessary to cease blood flow through the vessels or other ducts, and some procedures may require the use of a shunt. A surgical clip can thus be used to crimp the vessel or to secure the shunt to the vessel. Accordingly, a surgical clip applier, such as clip applier 10, can be introduced through the cannula or otherwise introduced into the surgical site to position the jaws 20 around the vessel, shunt, or other duct. The tissue stop 46 can facilitate positioning of the jaws 20 around the target site. The trigger 16 can then be actuated to cause a clip to be advanced between the jaws and positioned around the target site, and to cause the jaws 20 to close to crimp the clip. Depending on the intended use of the clip, the trigger 16 can be partially actuated, as indicated by the audible sound of the pawl 60 reaching the tock tooth 112 b, or it can be fully actuated. The trigger 16 is then released to release the partially or fully closed clip, and the procedure can be repeated if necessary to apply additional clips.

One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety. 

1. A surgical clip applier, comprising: a shaft having a proximal end and a distal end with opposed jaws thereon; a guide member disposed within the shaft and configured to guide a clip into the opposed jaws, the guide member having a channel formed in a surface thereof; and an advancer movably disposed within the shaft and configured to advance a clip over the guide member and into the opposed jaws, the advancer having a distal tip that slidably engages the channel for maintaining contact with a surgical clip as it is advanced into the opposed jaws.
 2. The surgical clip applier of claim 1, wherein the distal tip has a distal-facing surface that is configured to abut an apex of a surgical clip to advance the surgical clip into the opposed jaws.
 3. The surgical clip applier of claim 2, wherein the distal-facing surface of the distal tip has a height that is greater than a depth of the channel.
 4. The surgical clip applier of claim 1, wherein the channel of the guide member comprises an opening formed through the guide member.
 5. The surgical clip applier of claim 1, wherein a proximal portion of the channel has a ramped surface formed thereon and configured to abut against a proximal portion of the distal tip to cause a distal portion of the distal tip to deflect away from the guide member during proximal movement of the advancer.
 6. The surgical clip applier of claim 1, wherein a distal portion of the channel has a ramped surface formed thereon and configured to abut against a distal portion of the distal tip to cause the distal portion of the distal tip to deflect away from the guide member during distal movement of the advancer.
 7. The surgical clip applier of claim 1, wherein the guide member includes a longitudinally-extending groove formed therein and configured to substantially prevent lateral movement of the distal tip relative to opposed lateral sidewalls of the guide member.
 8. The surgical clip applier of claim 1, further comprising at least one clip disposed within the shaft, the clip having a maximum height measured in a direction transverse to a longitudinal axis of the shaft, and wherein the distal tip has a maximum height measured in a direction transverse to a longitudinal axis of the shaft that is greater than the height of the at least one clip.
 9. The surgical clip applier of claim 1, wherein the guide member comprises a tissue stop having a distal end with a recess formed therein for receiving tissue.
 10. The surgical clip applier of claim 1, wherein the opposed jaws are configured to engage opposed legs of a surgical clip such that an apex of the surgical clip is maintained a distance above the guide member during advancement of the surgical clip into the opposed jaws.
 11. A surgical clip applier, comprising: a shaft having opposed jaws on a distal end thereof, the opposed jaws being movable between open and closed positions for applying a clip to tissue; a clip advancer movably disposed within the shaft and having a distal tip configured to advance at least one clip into the opposed jaws; and an advancer guide disposed within the elongate shaft, the advancer guide having a ramped surface formed thereon and configured to cause a distal portion of the distal tip to deflect away from the guide member during proximal movement of the advancer to position the distal tip behind an apex of a surgical clip disposed within the shaft.
 12. The surgical clip applier of claim 11,wherein the advancer guide includes a channel formed therein, and the ramped surface is formed adjacent to a proximal end of the channel.
 13. The surgical clip applier of claim 11, wherein the ramped surface comprises a proximal ramped surface, and the guide member includes a distal ramped surface configured to cause the distal portion of the distal tip to deflect in a direction away from the guide member during distal movement of the advancer.
 14. The surgical clip applier of claim 13, wherein the advancer guide includes a channel formed therein, and the distal ramped surface is formed adjacent to a distal end of the channel.
 15. The surgical clip applier of claim 11, wherein the ramped surface is formed adjacent to a channel formed in the advancer guide, the channel being configured to receive the distal tip of the advancer therein.
 16. The surgical clip applier of claim 15, wherein the distal tip has a distal-facing surface that has a height that is greater than a depth of the channel in the advancer guide.
 17. The surgical clip applier of claim 15, wherein the advancer guide includes a distal longitudinally-extending channel formed therein and configured to slidably receive the distal tip of the advancer guide.
 18. A method for advancing a clip into opposed jaws of a clip applier, comprising: actuating a trigger to cause an advancer to move distally through a shaft and to contact and advance a surgical clip distally along a superior surface of a guide member and into opposed jaws of the clip applier, the advancer having a distal tip with a distal-facing surface that allows an apex of the surgical clip to move in superior and inferior directions while still maintaining contact with the apex of the surgical clip.
 19. The method of claim 18, further comprising releasing the trigger to move the advancer proximally, the distal tip of the advancer deflecting in an inferior direction beneath an inferior surface of a second surgical clip during proximal movement of the advancer.
 20. The method of claim 19, wherein, as the advancer moves proximally, the guide member causes the distal tip of the advancer to deflect in a superior direction to position the distal tip of the advancer at a location proximal to a second surgical clip.
 21. The method of claim 18, wherein the guide member includes a longitudinally-extending groove formed therein that maintains the distal tip of the advancer in alignment with a longitudinal axis of the guide member.
 22. The method of claim 18, wherein the advancer tip maintains contact with an apex of the clip as the clip is formed between the opposed jaws. 